SU1655675A1 - Method for obtaining permanent joint of pipes - Google Patents

Abstract

The invention relates to mechanical engineering, in particular, to a method for producing precision telescopic compounds from dissimilar materials having significant differences in thermal expansion coefficients (CTE), and can be used in instrument engineering, energy, chemical and other industries. The aim of the invention is to increase the reliability of the operation of a compound of dissimilar materials during thermal-cooling thermal cycling. At the upper end 6 of the outer pipe 7, an annular angular groove 8 is made and the radial grooves roll the walls of the groove on the mountaineer of the intermediate sleeve 3, fix the solder ring and perform the soldering. close to the CTE material of the outer pipe. The resulting compound retains its strength and tightness both after brazing and after heating to 100 ° C, while copper control telescopic telescopic joints with steel are destroyed during the cooling process after brazing 3 or 7 SP c o (L SP 10 VI ate

Description

The invention relates to mechanical engineering, in particular, to a method for producing precision telescopic compounds from dissimilar materials having significant differences in 9 thermal expansion coefficients (CTE), and can be used in instrument engineering, energy, chemical and other industries.

The purpose of the invention is to increase the reliability of the compound from dissimilar materials during the heating and cooling process at the thermocycling stage.

Figure 1 shows the design of the joint before rolling the groove and soldering walls; figure 2 - the same, after soldering: in fig.Z - section AA in figure 2.

The method is implemented as follows.

On the inner pipe 1, on its outer surface 2, the sleeve 3 is installed, which with the thinned end 4 is welded to the inner pipe by a seam 5. At the upper end 6 of the outer pipe 7, a curved annular groove 8 and radial grooves 9 are installed. After installing the outer pipe 7 on the sleeve 3, the wall of the corner groove 10 extends at the end of the sleeve at the weld 5. The sleeve is made of a material that is metallurgically compatible with the inner pipe, which allows to provide high-quality welding with high strength properties, and with KTR, close to the KTR of the outer Details. A solder ring 11 is installed in the annular groove 8, and brazing is applied. In the process of soldering, the solder fills the annular cavity, through the radial grooves, enters the cavity between the sleeve and the outer tube, forming an extended ply seam 12. The seamed walls of the corner groove 10 are completely immersed in the fillet part of the solder 13. In connection due to the fact that the seamed walls of the corner groove abut against the end of the sleeve and transfer axial loads to the weld seam of the sleeve — the internal pipe relaxes thermal stresses.

In the upper part of the weld, the relaxation of thermal stresses is due to plastic deformation (radial displacement) of the rolled-up walls of the corner groove, and in the lower part due to plastic deformation of the thinned part of the sleeve. This allows the joint to work reliably with temperature fluctuations during manufacture and during operation of joints of pipes made of dissimilar materials.

Example. In the process of obtaining a telescopic joint, the inner tube was made of steel 12x18Zh10T with a diameter of 3 mm, with a wall thickness of 1 mm, and the outer tube was made of tantalum

with a diameter of 8 mm and a wall thickness of 2 mm. The material of the sleeve was selected as 29 NC alloy. The sleeve had a diameter of 3.1 mm with a wall thickness in the thinned part equal to 0.3 mm. The sleeve was connected to a steel pipe by laser welding. Brazing was carried out with copper in a vacuum when heated by high-frequency currents.

The joint retains its strength and tightness both after soldering and after

heating to 1000 ° C while copper telescopic telescopic test compounds with steel were destroyed during cooling after brazing

Claims (1)

The invention The method of obtaining a non-detachable connection of pipes, including the installation of an intermediate sleeve, welding it thinned an end with an inner tube; a solder connection of the outer tube with a sleeve and an inner tube, characterized in that. that, in order to increase the reliability of the compound from dissimilar materials when thermal cycling heating - cooling, the sleeve is taken from the inner pipe material metallurgically compatible with the material and with a thermal expansion coefficient close to the thermal expansion coefficient of the outer pipe material, an angular groove is made at the end of the outer pipe and the groove wall is rolled onto the end surface of the sleeve. I “-SI t Ni F $ $$$$$ $$$ W : ъ i : s 05 L 01 U -1 ate